One of the most persistent problems encountered in the industrial truck art over the years has been to provide an upright construction which affords the operator of the truck good visibility through the upright, particularly in quadstage uprights.
Heretofore various means have been devised for improving operator visibility through multi-stage uprights of lift trucks while maintaining relatively simple and low cost construction. Previous attempts have included upright structures such as are disclosed in U.S. Pat. Nos. 2,788,863, 3,360,078, 3,394,778, 3,830,342 and 4,030,568. German Pat. No. 1,807,169 and German Publication (Offlegunschrifft) No. 2,020,276. In addition U.S. Patent applications Ser. Nos. 202,099 and 176,742 filed Oct. 30, 1980 and Aug. 11, 1980, respectively, and which have U.S. Pat. Nos. 4,374,550 and 4,401,191, respectively and, which are continuations of Ser. Nos. 17,779 and 28,291, filed Mar. 8, 1979 and Apr. 9, 1979, respectively, and which are both abandoned and both in the name of Richard J. Bartow, common assignee, disclose prior art of interest. Also, Ser. No. 17,779 is a continuation-in-part application of Ser. No. 842,765, filed Oct. 17, 1977 and also abandoned.